ABSTRACT
Renal cell carcinoma (RCC) accounts for approximately 2%-3% of human malignancies and is the most aggressive among urologic tumors. Biological heterogeneity, drug resistance, and chemotherapy side effects are the biggest obstacles to the effective treatment of RCC. The NF-κB transcription factor is one of several molecules identified to be responsible for the aggressive phenotype of this tumor. In the past decade, several studies have demonstrated the activation of NF-κB in RCC, and many have implicated NF-κB1 (p50) as an important molecule in tumor progression and metastasis. In the present study, a lentivirus was used to deliver shRNA targeting NF-κB1 into mouse RCC (Renca) cells. It was determined that the knockdown of the NF-κB1 gene led to a reduction in cell proliferation and late apoptosis/necrosis in vitro. Flow cytometry analysis demonstrated G2/M arrest in the cells. In addition, immunoblotting analysis revealed a significant increase in cyclin B1 and Bax. In vivo experiments showed that Renca-shRNA-NF-κB1 cells have significantly diminished tumorigenicity. Moreover, immunohistochemical analysis revealed an increase in necrotic areas of Renca-shRNA-NF-κB1 tumors. Thus, this study indicates that downregulation of NF-κB1 can suppress RCC tumorigenesis by inducing late apoptosis/necrosis. Therefore, NF-κB1 may be a potential therapeutic target for RCC.
Subject(s)
Carcinoma, Renal Cell/pathology , Kidney Neoplasms/pathology , NF-kappa B/biosynthesis , Animals , Apoptosis/physiology , Cell Line, Tumor , Cell Proliferation , Female , Gene Knockdown Techniques , Mice , Mice, Inbred BALB C , RNA, Small InterferingABSTRACT
Renal cell carcinoma (RCC) accounts for approximately 2%-3% of human malignancies and is the most aggressive among urologic tumors. Biological heterogeneity, drug resistance, and chemotherapy side effects are the biggest obstacles to the effective treatment of RCC. The NF-kappa B transcription factor is one of several molecules identified to be responsible for the aggressive phenotype of this tumor. In the past decade, several studies have demonstrated the activation of NF-kappa B in RCC, and many have implicated NF-kappa B1 (p50) as an important molecule in tumor progression and metastasis. In the present study, a lentivirus was used to deliver shRNA targeting NF-kappa B1 into mouse RCC (Renca) cells. It was determined that the knockdown of the NF-kappa B1 gene led to a reduction in cell proliferation and late apoptosis/necrosis in vitro. Flow cytometry analysis demonstrated G(2)/M arrest in the cells. In addition, immunoblotting analysis revealed a significant increase in cyclin B1 and Bax. In vivo experiments showed that Renca-shRNA-NF-kappa B1 cells have significantly diminished tumori genicity. Moreover, immunohistochemical analysis revealed an increase in necrotic areas of Renca-shRNA-NF-kappa B1 tumors. Thus, this study indicates that downregulation of NF-kappa B1 can suppress RCC tumorigenesis by inducing late apoptosis/necrosis. Therefore, NF-kappa B1 may be a potential therapeutic target for RCC.
ABSTRACT
Renal cell carcinoma (RCC) accounts for approximately 2%-3% of human malignancies and is the most aggressive among urologic tumors. Biological heterogeneity, drug resistance, and chemotherapy side effects are the biggest obstacles to the effective treatment of RCC. The NF-kappa B transcription factor is one of several molecules identified to be responsible for the aggressive phenotype of this tumor. In the past decade, several studies have demonstrated the activation of NF-kappa B in RCC, and many have implicated NF-kappa B1 (p50) as an important molecule in tumor progression and metastasis. In the present study, a lentivirus was used to deliver shRNA targeting NF-kappa B1 into mouse RCC (Renca) cells. It was determined that the knockdown of the NF-kappa B1 gene led to a reduction in cell proliferation and late apoptosis/necrosis in vitro. Flow cytometry analysis demonstrated G(2)/M arrest in the cells. In addition, immunoblotting analysis revealed a significant increase in cyclin B1 and Bax. In vivo experiments showed that Renca-shRNA-NF-kappa B1 cells have significantly diminished tumori genicity. Moreover, immunohistochemical analysis revealed an increase in necrotic areas of Renca-shRNA-NF-kappa B1 tumors. Thus, this study indicates that downregulation of NF-kappa B1 can suppress RCC tumorigenesis by inducing late apoptosis/necrosis. Therefore, NF-kappa B1 may be a potential therapeutic target for RCC.
ABSTRACT
BACKGROUND: Metastatic renal cell carcinoma (mRCC) is one of the most treatment-resistant malignancies. Despite all new therapeutic advances, almost all patients develop resistance to treatment and cure is rarely seen. In the present study, we evaluated the antitumor effect of a bicistronic retrovirus vector encoding both endostatin (ES) and interleukin (IL)-2 using an orthotopic metastatic RCC mouse model. METHODS: Balb/C-bearing Renca cells were treated with NIH/3T3-LendIRES-IL-2-SN cells. In the survival studies, mice were monitored daily until they died. At the end of the in vivo experiment, serum levels of IL-2 and ES were measured, the lung was weighed, and the number of metastatic nodules, nodule area, tumor vessels and proliferation of tumor-infiltrating Renca cells were determined. RESULTS: Inoculation of NIH/3T3-LendIRES-IL-2-SN cells resulted in an increase in ES and IL-2 levels in the treated group (p < 0.05). There was a significant decrease in lung wet weight, lung nodule area and tumor vessels in the treated group compared to the control group (p < 0.001). The proliferation of Renca cells in the bicistronic-treated group was significantly reduced compared to the control group (p < 0.05). Kaplan-Meier survival curves showed that the probability of survival was significantly higher for mice submitted to bicistronic therapy (log-rank test, p = 0.0016). Bicistronic therapy caused an increase in the infiltration of CD4, CD4 interferon (IFN)γ-producing, CD8, CD8 IFNγ-producing and natural killer (CD49b) cells. CONCLUSIONS: Retroviral bicistronic gene transfer led to the secretion of functional ES and IL-2 that was sufficiently active to: (i) inhibit tumor angiogenesis and tumor cell proliferation and (ii) increase the infiltration of immune cells.
